Magnetic device

ABSTRACT

A magnetic device comprising a magnetic body, a coil disposed in the magnetic body and at least one thermal conductive layer, wherein a first portion of the at least one thermal conductive layer encapsulates at least one portion of the coil and a second portion of the at least one thermal conductive layer is exposed from the magnetic body, wherein the at least one thermal conductive layer forms a continuous thermal conductive path from the coil to the outside of the magnetic body for dissipating heat generated from the coil.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication Ser. No. 62/822,048 filed on Mar. 22, 2019, which is herebyincorporated by reference herein and made a part of the specification.

BACKGROUND OF THE INVENTION I. Field of the Invention

The invention relates to an electronic structure and, in particular, toa stacked electronic structure.

II. Description of the Related Art

Electronic structures, such as power modules and DC-DC converters,typically include electronic devices having interconnecting circuitryelectrically connected to a substrate. The devices are coupled to leadsfor connection to conductive patterns and/or other electronicassemblies.

One conventional approach for reducing the surface area occupied by theelectronic structures in compact electronic products is to stack theassembled devices. However, the heat generated from the coil is hard todissipate.

Furthermore, the heat generated by the stacked electronic devices isalso hard to dissipate.

Accordingly, there is demand for a better solution to solve theseproblems.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, a magnetic device isdisclosed, wherein the magnetic device comprises a magnetic body, a coildisposed in the magnetic body and at least one thermal conductive layer,wherein a first portion of the at least one thermal conductive layerencapsulates at least one portion of the coil and a second portion ofthe at least one thermal conductive layer is exposed from the magneticbody, wherein the at least one thermal conductive layer forms acontinuous thermal conductive path from the coil to the outside of themagnetic body for dissipating heat generated from the coil.

In one embodiment, the at least one thermal conductive layer comprises athermal conductive and adhesive layer encapsulates an inner surface ofthe coil.

In one embodiment, the thermal conductive and adhesive layer furtherencapsulates an outer surface of the coil.

In one embodiment, the at least one thermal conductive layer comprises athermal conductive and adhesive layer and a metal layer, wherein a firstportion of the thermal conductive and adhesive layer encapsulates aninner surface of the coil and a second portion of the thermal conductiveand adhesive layer is disposed over a top surface or a bottom surface ofthe coil, wherein the thermal conductive and adhesive layer adheres thecoil to a corresponding portion of the magnetic body, and the metallayer is overlaid on the second portion of the thermal conductive andadhesive layer and extended to an outer surface of the magnetic body fordissipating heat generated from the coil.

In one embodiment, the at least one thermal conductive layer comprises athermal conductive and adhesive layer, a first metal layer and a secondmetal layer, wherein a first portion of the thermal conductive andadhesive layer encapsulates an inner surface of the coil, a secondportion of the thermal conductive and adhesive layer is disposed over atop surface of the coil, and a third portion of the thermal conductiveand adhesive layer is disposed over a bottom surface of the coil,wherein the first metal layer is overlaid on the second portion, and thesecond metal layer is overlaid on the third portion of the thermalconductive and adhesive layer, wherein each of the first metal layer andthe second metal layer is extended to a corresponding outer surface ofthe magnetic body for dissipating heat generated from the coil.

In one embodiment, the magnetic device is an inductor.

In one embodiment, the magnetic device is a choke.

In one embodiment, each of the at least one thermal conductive layer hasa thermal conductivity: K>0.5 W/mK.

In one embodiment, the thermal conductive layer comprises at least oneof the following material: copper foil, thermal paste, thermal glue,thermal tape, copper pillar, graphite, and etc.

In one embodiment, the at least one thermal conductive layer comprises afirst thermal conductive layer comprising thermal conductive andadhesive material that is disposed between said inner surface of thecoil and a portion of the magnetic body disposed in the hollow space ofthe coil.

In one embodiment, the at least one thermal conductive layer furthercomprises a second thermal conductive layer comprising metal that isdisposed between a bottom surface of the coil and a portion of themagnetic body disposed under said bottom surface of the coil, whereinthe second thermal conductive layer extends to an outer surface of themagnetic body.

In one embodiment, the magnetic body comprises an I core, wherein aportion of the at least one thermal conductive layer is disposed betweensaid inner surface of the coil and the pillar of the I core.

In one embodiment, the magnetic body comprises a T core, wherein aportion of the at least one thermal conductive layer is disposed betweensaid inner surface of the coil and the pillar of the T core.

In one embodiment, a stacked electronic structure is disclosed, whereinthe stacked electronic structure comprises: a substrate, wherein aplurality of electronic devices are disposed on and electricallyconnected to the substrate, wherein a molding body encapsulates theplurality of electronic devices, a first thermal conductive layer isdisposed on a first electronic device and a second thermal conductivelayer is disposed on a second electronic device, wherein the firstthermal conductive layer and the second thermal conductive layer areseparated by a gap; and a magnetic device, comprising a magnetic bodydisposed over a top surface of the molding body, wherein at least onethird thermal conductive layer encapsulates the magnetic body, whereinthe at least one third thermal conductive layer comprises a firstterminal portion and a second terminal portion, wherein the firstterminal portion and the second terminal portion are separated by a gap,and the first thermal conductive layer and the second thermal conductivelayer are respectively connected with the first terminal portion and thesecond terminal portion for heat dissipation.

In one embodiment, the at least one third thermal conductive layercomprises a third metal layer that encapsulates the top surface of themagnetic body and extends to the first terminal portion and the secondterminal portion through a first lateral surface.

In one embodiment, the at least one third thermal conductive layercomprises a third metal layer that encapsulates the top surface of themagnetic body and extends to the first terminal portion through a firstlateral surface and the second terminal portion through a second lateralsurface opposite to the first lateral surface.

In one embodiment, the third metal layer extends to a third terminalportion and a fourth terminal portion through a second lateral surfaceopposite to the first lateral surface.

In one embodiment, the first terminal portion of the third metal layeris extended to a first portion of the bottom surface of the magneticbody, and the second terminal portion of the third metal layer isextended to a second portion of the bottom surface of the magnetic body,wherein the first terminal portion and the second terminal portion areelectrically connected to the first metal layer and the second metallayer, respectively.

In one embodiment, the at least one third thermal conductive layercomprises a third metal layer and a fourth metal layer, wherein thethird metal layer and the fourth metal layer are separated by a gap,wherein the third metal layer encapsulates a first portion of the topsurface of the magnetic body and extends to the first terminal portionthrough a first lateral surface, and the fourth metal layer encapsulatesa second portion of the top surface of the magnetic body and extends tothe second terminal portion through the first lateral surface.

In one embodiment, the third metal layer extends to a third terminalportion through a second lateral surface opposite to the first lateralsurface, and the fourth metal layer extends to a fourth terminal portionthrough the second lateral surface.

In one embodiment, the first metal layer and the second metal layer arerespectively in contact with the first terminal portion and the secondterminal portion for heat dissipation. In one embodiment, wherein eachof said metal layer is electrically connected to a ground.

In one embodiment, wherein the first metal layer encapsulates a topsurface of the first electronic device.

In one embodiment, wherein the first metal layer encapsulates a topsurface and a plurality of lateral surfaces of the first electronicdevice.

In one embodiment, wherein the second metal layer encapsulate a topsurface of the second electronic device.

In one embodiment, wherein the second metal layer encapsulate a topsurface and a plurality of lateral surfaces of the second electronicdevice.

In one embodiment, wherein each of the first electronic device and thesecond electronic device is a MOSFET.

In one embodiment, the first electrode of the magnetic device iselectrically connected to a first conductive pillar disposed on thesubstrate.

In one embodiment, a second electrode of the magnetic device iselectrically connected to a second conductive pillar disposed on thesubstrate.

In one embodiment, the plurality of electronic devices comprises an ICand a MOSFET.

In one embodiment, the molding body further encapsulates the conductivepillars with a top surface of each of the conductive pillars exposedfrom the molding body.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent description and examples with references made to theaccompanying drawings, wherein:

FIG. 1A-1D each shows a partially schematic, cross-sectional side viewof a magnetic device in accordance with a corresponding embodiment ofthe invention;

FIG. 1E-1F is a partially schematic, cross-sectional side view of a coilencapsulated by a thermal conductive layer in accordance with anotherembodiment of the invention;

FIG. 2A is a layout of a stacked electronic structure in accordance withone embodiment of the invention;

FIG. 2B-2C is a partially schematic of a stacked electronic structure inaccordance with one embodiment of the invention;

FIG. 2D-2E is a partially schematic of a stacked electronic structure inaccordance with one embodiment of the invention;

FIG. 2F-2G is a partially schematic of a stacked electronic structure inaccordance with one embodiment of the invention;

FIG. 3A-3C is a partially schematic of a stacked electronic structure inaccordance with one embodiment of the invention;

FIG. 4 shows a comparison of thermal resistances of some of the stackedelectronic module of the present invention to the conventionaltechnology.

FIG. 5A shows a top view of a magnetic device in accordance with anembodiment of the invention;

FIG. 5B shows a bottom view of the magnetic device in FIG. 5A inaccordance with an embodiment of the invention;

FIG. 5C shows a top view of the module in FIG. 5A in accordance with anembodiment of the invention;

FIG. 6A shows a top view of a magnetic device in accordance with anembodiment of the invention;

FIG. 6B shows a bottom view of the magnetic device of FIG. 6A inaccordance with an embodiment of the invention;

FIG. 6C shows a top view of a magnetic device in accordance with anembodiment of the invention; and

FIG. 7A-7D shows heat simulation results of the module in accordancewith an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

It is understood that the following disclosure provides many differentembodiments, or examples, for implementing different features of theinvention. Specific examples of devices and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features are formed between the first and second features,such that the first and second features are not in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

FIG. 1A is a partially schematic, cross-sectional side view of amagnetic device in accordance with one embodiment of the invention. Asshown in FIG. 1A, wherein an magnetic device comprises a magnetic body101, a coil 102 disposed in the magnetic body 101, and a first thermalconductive layer 104, wherein a first portion 104 a of the first thermalconductive layer 104 is disposed between an inner surface of the coiland a first portion 101 a of the magnetic body 101 disposed in thehollow space of the coil 102, and a second portion 104 b of the firstthermal conductive layer 104 is exposed from the magnetic body 101 todissipate heat generated from the coil 102.

In one embodiment, the magnetic body 101 comprises a T core 101T,wherein the first portion 104 a of the first thermal conductive layer104 is disposed between the inner surface of the coil 102 and the pillar101 a of the T core 101T, wherein the second portion 104 b of the firstthermal conductive layer 104 is disposed on an outer surface of the ofthe T core 101T to dissipate heat from the coil.

In one embodiment, a third portion 104 b 1 of the first thermalconductive layer 104 is disposed on an outer surface of the T core 101Tto dissipate heat from the coil.

In one embodiment, the magnetic device is an inductor.

In one embodiment, the magnetic device is a choke.

In one embodiment, the first thermal conductive layer 104 has a thermalconductivity: K>0.5 W/mK.

In one embodiment, the coverage of the coil by the first thermalconductive layer 104 is 5˜100%.

In one embodiment, the first thermal conductive layer 104 comprises atleast one of the following material: copper foil, thermal paste, thermalglue, thermal tape, copper pillar, graphite, and etc.

In one embodiment, the first thermal conductive layer 104 comprisesthermal conductive and adhesive material to be adhered to the coil.

In one embodiment, the first thermal conductive layer 104 extends to anouter surface of the magnetic body.

FIG. 1B is a partially schematic, cross-sectional side view of amagnetic device in accordance with one embodiment of the invention. Asshown in FIG. 1B, wherein an magnetic device comprises a magnetic body101, a coil 102 disposed in the magnetic body 101, and a first thermalconductive layer 104, wherein a first portion 104 a of the first thermalconductive layer 104 is disposed between an inner surface of the coiland a first portion 101 a of the magnetic body 101 disposed in thehollow space of the coil 102, wherein a first portion 105 a of a secondthermal conductive layer 105 is disposed on a corresponding portion 104c of the first thermal conductive layer 104 and a second portion 105 bof the second thermal conductive layer 105 extends to an outer surfaceof the magnetic body 101, wherein the first thermal conductive layer 104and the second thermal conductive 105 forms a continuous thermalconductive path to dissipate heat generated from the coil 102.

In one embodiment, the magnetic body comprises a T core 101T, whereinthe first portion 104 a of the first thermal conductive layer 104 isdisposed between the inner surface of the coil 102 and the pillar 101 aof the T core 101T, wherein the second portion 105 b of the secondthermal conductive layer 105 is disposed on an outer surface of the Tcore 101T.

In one embodiment, a third portion 105 b 1 of the second thermalconductive layer 105 is disposed on an outer surface of the T core 101Tto dissipate heat from the coil.

In one embodiment, the second thermal conductive layer 105 comprises atleast one of the following material: copper foil, thermal paste, thermalglue, thermal tape, copper pillar, graphite, and etc.

In one embodiment, the second thermal conductive layer 105 has a thermalconductivity: K>0.5 W/mK.

In one embodiment, the magnetic body 101 comprises a I core, as shown inFIG. 1C and FIG. 1D, which are described in below.

FIG. 1C is a partially schematic, cross-sectional side view of amagnetic device in accordance with one embodiment of the invention. Asshown in FIG. 1C, wherein an magnetic device comprises a magnetic body101, a coil 102 disposed in the magnetic body 101, and a first thermalconductive layer 104, wherein a first portion 104 a of the first thermalconductive layer 104 is disposed between an inner surface of the coiland a first portion 101 a of the magnetic body 101 disposed in thehollow space of the coil 102 and a second portion 104 b of the firstthermal conductive layer 104 is exposed from the magnetic body 101 todissipate heat generated from the coil 102.

In one embodiment, the magnetic body 101 comprises a I core 101 i, asshown in FIG. 1C, wherein the first portion 104 a of the first thermalconductive layer 104 is disposed between the inner surface of the coil102 and the pillar 101 a of the I core 101 i, wherein the second portion104 b of the first thermal conductive layer 104 is disposed on an outersurface of the of the I core 101 i.

In one embodiment, a third portion 104 b 1 of the first thermalconductive layer 104 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

In one embodiment, a fourth portion 104 b 2 of the first thermalconductive layer 104 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

In one embodiment, a fifth portion 104 b 3 of the first thermalconductive layer 104 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

FIG. 1D is a partially schematic, cross-sectional side view of amagnetic device 100 in accordance with one embodiment of the invention.As shown in FIG. 1D, wherein an magnetic device comprises a magneticbody 101, a coil 102 disposed in the magnetic body 101, and a firstthermal conductive layer 104, wherein a first portion 104 a of the firstthermal conductive layer is disposed between an inner surface of thecoil 102 and a first portion 101 a of the magnetic body 101 disposed inthe hollow space of the coil 102, wherein a first portion 105 a of asecond thermal conductive layer 105 is disposed on the first thermalconductive layer 104 and a second portion 105 b of the second thermalconductive layer 105 extends to an outer surface of the magnetic body101, wherein the first thermal conductive layer 104 and the secondthermal conductive 105 forms a continuous thermal conductive path todissipate heat generated from the coil 102.

In one embodiment, as shown in FIG. 1D, the magnetic body 101 comprisesa I core 101 i, wherein the first portion 104 a of the first thermalconductive layer 104 is disposed between the inner surface of the coil102 and the pillar 101 a of the I core 101 i, wherein the second portion105 b of the second thermal conductive layer 105 is disposed on an outersurface of the of the I core 101 i.

In one embodiment, a third portion 105 b 1 of the second thermalconductive layer 105 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

In one embodiment, a fourth portion 105 b 2 of the second thermalconductive layer 105 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

In one embodiment, a fifth portion 105 b 3 of the second thermalconductive layer 105 is disposed on an outer surface of the I core 101 ito dissipate heat from the coil.

Please note that there are many ways to form the magnetic body 101, forexample, the magnetic body 101 can comprise a T core and a magneticmaterial encapsulating the coil and the T core, or the magnetic body 101can comprise an I core and a magnetic material encapsulating the coiland the I core, or the entire magnetic body 101 can be integrallyformed, that is, the material encapsulating the coil also fills into thehollow space of the coil.

Please note that there are many ways to encapsulate at least one portionof the coil. For example, the thermal conductive layer can encapsulatean inner surface of the coil, or the thermal conductive layer canencapsulate an outer surface of the coil, or the thermal conductivelayer can encapsulate an inner surface of the coil and an outer surfaceof the coil.

In one embodiment, the thermal conductive layer can encapsulate theentire surface of the coil for heat dissipation.

In one embodiment, as shown in FIG. 1E, the first thermal conductivelayer 104 comprises a T shape portion that is in contact with the wireforming the coil wherein the terminal portions 104 e of the firstthermal conductive layer 104 can be used for exposing the first thermalconductive layer 104 from the molding body for heat dissipation.

In one embodiment, as shown in FIG. 1F, the first thermal conductivelayer 104 comprises a circular shape portion that encapsulates the wireforming the coil, wherein the terminal portions 104 e of the firstthermal conductive layer 104 can be used for exposing the first thermalconductive layer 104 from the molding body for heat dissipation.

In one embodiment, the coverage of the coil by the thermal conductivelayers is 5˜100%.

In one embodiment, a stacked electronic structure is disclosed. Pleaserefer to FIG. 2A, FIG. 2B and FIG. 2C, wherein the stacked electronicstructure comprises: a substrate 205, a plurality of electronic devices207A, 207B, 209 disposed on and electrically connected to the substrate205, wherein a first thermal conductive layer 207AH is disposed on afirst electronic device 207A and a second thermal conductive layer 207BHis disposed on a second electronic device 207B, wherein the firstthermal conductive layer 207AH and the second thermal conductive layer207BH are separated by a gap as shown in FIG. 2A, wherein a molding body210 encapsulates the plurality of electronic devices 207A, 207B, 209, asshown in FIG. 2C in which 207AH and 207BH are shown for illustrationpurpose; and a magnetic device 201, comprising a magnetic body 201Bdisposed over a top surface of the molding body 210, wherein a thirdthermal conductive layer 201M encapsulates the magnetic body 201B,wherein the third thermal conductive layer 201M comprises a firstterminal portion 201 a and a second terminal portion 201 b, wherein thefirst terminal portion 201 a and the second terminal portion 201 b areseparated by a gap, and the first thermal conductive layer 207AH and thesecond thermal conductive layer 207BH are respectively connected withthe first terminal portion 201 a and the second terminal 201 b portionfor heat dissipation, as shown in FIG. 2B and FIG. 2C.

Please note that the first terminal portion 201 a and the secondterminal 201 b portion can be located at a same lateral side of themagnetic body 201B, or the first terminal portion 201 a and the secondterminal 201 b portion can be located at different lateral sides of themagnetic body 201B, or the first terminal portion 201 a and the secondterminal 201 b portion can be disposed on the bottom surface of themagnetic body 201B.

In one embodiment, as shown in FIG. 2B, wherein another thermalconductive layer 209H can be disposed on a corresponding passiveelectronic device for dissipate heat.

In one embodiment, the third thermal conductive layer 201M furthercomprises a third terminal portion 201 c and a fourth terminal portion201 d, wherein the third terminal portion 201 c and the fourth terminalportion 201 d are separated by a gap. By doing do, the third thermalconductive layer 201M encapsulating the magnetic body 201B can have atleast two terminal portions to electrically connected with the thermalconductive layers such as 207AH, 207BH, 219H to dissipate heat generatedfrom the corresponding electronic devices 207A, 207B, 219 as shown inFIG. 2C.

In one embodiment, as shown in FIG. 2C, metal layers 215, 216, 217 canbe disposed on the molding body 210, and the terminal portions, such asthe first terminal portion 201 a and the second terminal 201 b portion,can be electrically connected with the first thermal conductive layer207AH and the second thermal conductive layer 207BH via the metal layers215, 216, 217 to dissipate heat generated from the correspondingelectronic devices 207A, 207B.

In one embodiment electronic devices 207A, 207B are active devices.

In one embodiment electronic devices 207A, 207B are MOSFET.

In one embodiment, the substrate 205 is a BT (Bismaleimide Triazine)board, metallic substrate or ceramic substrate.

In one embodiment, the first electrode of the magnetic device iselectrically connected to a first pin 250, such as a conductive pillar,disposed on the substrate, as shown in FIG. 2A.

In one embodiment, a second electrode of the magnetic device iselectrically connected to a second pin 251, such as a conductive pillardisposed on the substrate as shown in FIG. 2A.

In one embodiment, as shown in FIG. 2E, a metal layers 218 can bedisposed on the molding body 210 and the terminal portions such as thefirst terminal portion 201 a and the second terminal portion 201 c, canbe electrically connected with the first thermal conductive layer 207AHand the second thermal conductive layer 207BH via the metal layers 218to dissipate heat.

In one embodiment, each of the terminal portions 201 a, 201 b, 201 c,201 d is extended inwardly, that is, each of the terminal portions 201a, 201 b, 201 c, 201 d is extended to a bottom surface of the magneticbody 201B. In one embodiment, the electrode 222 of the coil can belocated between the first terminal portion 201 a and the second terminalportion 201 b.

In one embodiment, as shown in FIG. 2D, metal layers 218 and 219 can bedisposed on the molding body 210, wherein terminal portion 201 b andterminal portion 201 d can be electrically connected with the metallayer 218 and terminal portion 201 a and terminal portion 201 c can beelectrically connected with the metal layer 219 to dissipate heatgenerated from the corresponding electronic devices.

In one embodiment, the third thermal conductive layer 201M comprises ametal layer and the metal layer is attached to the magnetic body 201B bya thermal conductive and adhesive material.

In one embodiment, the third thermal conductive layer 201M comprises ametal plate and the metal plate is attached to the magnetic body 201B bya thermal conductive and adhesive material.

In one embodiment, the third thermal conductive layer 201M comprisingmetal is electrically connected to a ground for heat dissipation andreducing EMI.

In one embodiment, the third thermal conductive layer 201M encapsulatesa top surface and a plurality of lateral surfaces of the magnetic body201B for heat dissipation.

In one embodiment, the third thermal conductive layer 201M encapsulatesa top surface and four lateral surfaces of the magnetic device 201 forheat dissipation.

In one embodiment, the third thermal conductive layer 201M comprises afolded metal plate that encapsulates the top surface and the pluralityof lateral surfaces of the magnetic device.

In one embodiment, the third thermal conductive layer 201M is integrallyformed.

In one embodiment, at least one portion of the third thermal conductivelayer 201M is electroplated on the top surface and the plurality oflateral surfaces of the magnetic device.

In one embodiment, the magnetic device 201 is an inductor.

In one embodiment, the magnetic device 201 is a choke.

In one embodiment, the third thermal conductive layer 201M shown in FIG.2B-2D can be separated into two thermal conductive layers such as twoseparated metal layer 201L, 201R as shown in FIG. 3A, wherein the metallayer 201L comprises the first terminal portion 201 a and the thirdterminal portion 201 c, the metal layer 201R comprises the secondterminal portion 201 b and the fourth terminal portion 201 d, whereineach of the terminal portions 201 a, 201 b, 201 c, 201 d is extendedoutwardly, that is, each of the terminal portions 201 a, 201 b, 201 c,201 d is extended away from the magnetic body 201B.

In one embodiment, the electrode 222 of the coil can be located betweenthe first terminal portion 201 a and the second terminal portion 201 b.

In one embodiment, the third thermal conductive layer 201M shown in FIG.2B-2D can be separated into two thermal conductive layers such as twoseparated metal layers 201L, 201R as shown in FIG. 3B, wherein the metallayer 201L comprises the first terminal portion 201 a and the thirdterminal portion 201 c, the metal layer 201R comprises the secondterminal portion 201 b and the fourth terminal portion 201 d, whereineach of the terminal portions 201 a, 201 b, 201 c, 201 d is extendedinwardly, that is, each of the terminal portions 201 a, 201 b, 201 c,201 d is extended to a bottom surface of the magnetic body 201B, whereinthe metal layer 201L is extended to the bottom surface through a firstlateral surface to a bottom surface of the magnetic body 201B, the metallayer 201R is extended to the bottom surface through the first lateralsurface to a bottom surface of the magnetic body 201B, wherein a portionof the electrode of the coil is disposed on the first lateral surfaceadjacent to the first lateral surface.

In one embodiment, the third thermal conductive layer 201M shown in FIG.2B-2D can be separated into two thermal conductive layers such as twoseparated metal layers 201L, 201R as shown in FIG. 3C, wherein the metallayer 201L comprises the first terminal portion 201 a and the thirdterminal portion 201 c, the metal layer 201R comprises the secondterminal portion 201 b and the fourth terminal portion 201 d, whereineach of the terminal portions 201 a, 201 b, 201 c, 201 d is extendedinwardly, that is, each of the terminal portions 201 a, 201 b, 201 c,201 d is extended to a bottom surface of the magnetic body 201B, whereinthe metal layer 201L is extended to the bottom surface through a secondlateral surface to a bottom surface of the magnetic body 201B, the metallayer 201R is extended to the bottom surface through a fourth lateralsurface to a bottom surface of the magnetic body 201B, wherein thesecond lateral surface is opposite to the fourth lateral surface,wherein a portion of the electrode of the coil is disposed on the firstlateral surface adjacent to the second lateral surface.

In one embodiment, each of the metal layers 201L, 201R comprises afolded metal plate that encapsulates the top surface and the pluralityof lateral surfaces of the magnetic device.

In one embodiment, each of the metal layers 201L, 201R is integrallyformed.

In one embodiment, at least one portion of each of the metal layers201L, 201R is electroplated on the top surface and the plurality oflateral surfaces of the magnetic device.

In one embodiment, each of the metal layers 201L, 201R is connected to aground for dissipating heat and reducing EMI.

For example, as shown in FIG. 4 , the thermal resistance of a MOSFET ina conventional electronic module without heat dissipation metal layer is12.07, which can be reduced to 4.84 by using the stacked electronicmodule having the metal layers 201L, 201R.

In one embodiment, as shown in FIG. 5A, an insulating layer 280, such asan insulating layer sheet, can be disposed on the bottom surface of themagnetic body 201B for preventing short circuits occur between themagnetic body and the module 210, wherein the metal layer 201L comprisesthe first terminal portion 201 a, and the metal layer 201R comprises thesecond terminal portion 201 b, the terminal portion 201 a, 201 b can bedisposed on the bottom surface of the insulating layer 280, as shown inFIG. 5B, wherein each of the terminal portions 201 a, 201 b is extendedinwardly, that is, each of the terminal portions 201 a, 201 b isextended to a bottom surface of the magnetic body 201B, wherein themetal layer 201L is extended to the bottom surface through a secondlateral surface to a bottom surface of the magnetic body 201B, the metallayer 201R is extended to the bottom surface through a fourth lateralsurface to a bottom surface of the magnetic body 201B, wherein thesecond lateral surface is opposite to the fourth lateral surface,wherein a portion of the electrode 222 of the magnetic device isdisposed on the first lateral surface adjacent to the second lateralsurface.

In one embodiment, a bottom surface of the insulating layer sheet 280 isaligned with a bottom surface of the first terminal portion 201 a and abottom surface of the second terminal portion 201 b, so as to from asubstantially flat surface for mounting the magnetic device on themodule 210, wherein the first terminal portion 201 a and the secondterminal portion 201 b can be electrically connected to a pad 250 on atop surface of the module 210, and the electrode 222 of the magneticdevice, such as an inductor, can be electrically connected to a pad 251on a top surface of the module 210, as shown on FIG. 5C.

In one embodiment, as shown in FIG. 6A, the metal layer 201M comprises afirst terminal portion 201 a and a second terminal portion 201 b,wherein each of the terminal portions 201 a, 201 b is extended inwardly,that is, each of the terminal portions 201 a, 201 b is extended to abottom surface of the magnetic body 201B, wherein the metal layer 201Mis extended to the bottom surface through a second lateral surface and afourth lateral surface of the magnetic body 201B, wherein the secondlateral surface is opposite to the fourth lateral surface, wherein aportion of the electrode of the magnetic device, such as an inductor, isdisposed on the first lateral surface adjacent to the second lateralsurface.

In one embodiment, as shown in FIG. 6B, the metal layer 201M comprises afirst opening 201 ah that is formed in the terminal portion 201 a andextended to the second surface of the magnetic body 201B and a secondopening 201 bh that is formed in the terminal portion 201 b and extendedto the fourth surface of the magnetic body 201B, so that the solderingmaterial can be disposed in the openings 201 ah, 201 bh for making theconnectivity between the magnetic device, such as an inductor, and themodule 210 more reliable.

In one embodiment, as shown in FIG. 6C, an insulating layer 290 can bedisposed on the top surface of the magnetic body 201B and the metallayer 201M can be disposed on the insulating layer 290. In oneembodiment, the insulating layer 290 is a mylar sheet.

FIG. 7A shows the heat distribution of the module 210 based on a thermalsimulation result without a heat sink for dissipating heat from themodule 210; FIG. 7B shows the heat distribution of the module 210 basedon a thermal simulation result with the heat-sink structure of thepresent invention for dissipating heat from the module 210, wherein thelevels of the heat generated from components or areas of the module 210is shown by the colors in FIG. 7C. The simulation results show that,with the heat-sink structure of the present invention for dissipatingheat from the module 210, the maximum temperature is 52.925 (° C.) andthe maximum thermal resistance is 8.514 (K/W) compared with the maximumtemperature: 98.061 (° C.) and the maximum thermal resistance: 22.439(K/W) without the heat sink for dissipating heat from the module 210, asshown in FIG. 7D.

From the foregoing, it will be appreciated that, although specificembodiments have been described herein for purposes of illustration,various modifications may be made without deviating from the spirit andscope of the disclosure. Furthermore, where an alternative is disclosedfor a particular embodiment, this alternative may also apply to otherembodiments even if not specifically stated.

What is claimed is:
 1. A magnetic device, comprising: a magnetic body,comprising a T-core and a unitary molding body, wherein the T-corecomprises a base and a pillar that is disposed on a top surface of thebase; a coil, disposed in the magnetic body and wound around the pillarof the T-core, wherein the unitary molding body encapsulates the pillarof the T-core and the coil with a first portion of the unitary moldingbody covering a top surface of the pillar and a top surface of the coiland a second portion of the unitary molding body being in contact withan outer lateral surface of the coil; and at least one thermalconductive layer, wherein a first portion of the at least one thermalconductive layer encapsulates at least one portion of the coil and asecond portion of the at least one thermal conductive layer is exposedfrom the magnetic body, wherein said first portion of the at least onethermal conductive layer comprises a portion that is disposed between aninner side surface of the coil and a side surface of the pillar of theT-core, and the at least one thermal conductive layer forms a continuousthermal conductive path from the coil to the outside of the magneticbody for dissipating heat generated from the coil.
 2. The magneticdevice as claimed in claim 1, wherein the magnetic device is aninductor.
 3. The magnetic device as claimed in claim 1, wherein themagnetic device is a choke.
 4. The magnetic device as claimed in claim1, wherein the at least one thermal conductive layer has a thermalconductivity: K>0.5 W/mK.
 5. The magnetic device as claimed in claim 1,wherein the at least one thermal conductive layer is selected from oneof the following materials: copper foil, thermal paste, thermal glue,thermal tape, copper pillar, and graphite.